[Qemu-devel] [PATCH 2/4] s390x/css: fix NULL handling for CCW addresses

[Halil Pasic <pasic@linux.vnet.ibm.com>]

Back then in the time of df1fe5bb49 ("s390: Virtual channel subsystem
support.", 2013-01-24) -EIO used to map to a channel-program check (via
the default label of the switch statement).  Then 2dc95b4cac
("s390x/3270: 3270 data stream handling", 2016-04-01) came along
and that changed dramatically.

Let us roll back this undesired side effect, and go back to
channel-program check.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Fixes: 2dc95b4cac "s390x/3270: 3270 data stream handling"
---

I'm not sure 0 as CCW address  it's strictly illegal. Yes 0 is an
unlikely address for a CCW but I would appreciate a PoP reference
clarifying this...

Another reason to not use Unix/POSIX error codes like this.
---
 hw/s390x/css.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 09f6ba0310..a44d87ab3e 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -793,7 +793,7 @@ static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr,
     CCW1 ccw;
 
     if (!ccw_addr) {
-        return -EIO;
+        return -EINVAL; /* channel-program check */
     }
     /* Check doubleword aligned and 31 or 24 (fmt 0) bit addressable. */
     if (ccw_addr & (sch->ccw_fmt_1 ? 0x80000007 : 0xff000007)) {
-- 
2.13.5